Devices for applying digital signatures (hereinafter "digital signature devices" or DSD) form a rapidly developing branch of the art. A Digital Signature Standard has been published by the American NIST (NIST-DSS). However, this Standard, and all methods for performing cryptographic operations that have been suggested in connection with digital signature devices (hereinafter "DSD") involve the use of relatively complicated, and therefore expensive, hardware and/or software.
It is a purpose of this invention to provide a DSD that is simplified from the hardware viewpoint and hence is less expensive.
It is another purpose of this invention to provide new and improved circuits that are particularly useful to provide a preferred from of such a DSD, but can be used without connection with this latter to perform cryptographic operations.
It is a further purpose of this invention to provide methods for performing crytoographic operations by means of a DSD according to the invention.
A still further purpose of the invention is to provide a hardware-software package that can be integrated into a form of electronic card (electronic integrated circuit, PC board, and the like) that can implement the NIST-DSS process, the RSA process, and other public key cryptographic operations.
A further purpose of the invention is to provide methods for executing cryptographic operations regardless of the software or hardware means for executing them.
Other purposes and advantages of the invention will appear as the description proceeds.